1. Field of the Invention
The present invention relates to a display device that compensates for variations in characteristics of driving transistors of pixels and a method of driving the same.
2. Description of the Related Art
Recently, various flat panel display devices having reduced weight and volume, which are unfavorable aspects of a cathode ray tube, have been developed. Examples of flat panel display devices include liquid crystal displays, field emission displays, plasma display panels, organic light emitting displays, and others.
Among these flat panel display devices, the organic light emitting display displays images using an organic light emitting diode that generates light through the recombination of electrons and holes. Attention has been particularly paid to the organic light emitting display, which has a fast response speed, is driven with low power consumption, and exhibits excellent luminous efficiency, luminance, and viewing angle.
Typically, the organic light emitting displays (OLEDs) are classified into a passive matrix OLED (PMOLED) and an active matrix OLED (AMOLED) according to a driving scheme of an organic light emitting diode. The AMOLED selecting and lighting each unit pixel has been mainly used in view of better resolution, contrast, and operation speed.
Each pixel of the active matrix OLED includes an organic light emitting diode, a driving transistor that controls the amount of current supplied to the organic light emitting diode, and a switching transistor that transmits a data signal to the driving transistor in order to control the amount of light emitted from the organic light emitting diode.
The driving transistor has to be continuously turned on so that the organic light emitting diode can emit light. In the case of a large panel, variations in characteristics of the driving transistors of different pixels exist, and a moiré pattern is generated due to the variations in the characteristics. The variations in the characteristics of the driving transistors indicate variations in threshold voltage and mobility of the driving transistors. Even if the same data voltage is transmitted to gate electrodes of each of the driving transistors, the currents flowing through the driving transistors are different from each other depending on the variations in the characteristics of the plurality of driving transistors.
As a result, the moiré phenomenon occurs, and thereby image quality characteristics are deteriorated. Thus, it is necessary to compensate for these variations of driving transistors between pixels of a display device in order to improve the image quality.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention, and therefore it may contain information that does not constitute prior art as per 35 U.S.C. §102 to a person of ordinary skill in the art.